package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * @author Yandel
 * @date 2025/7/20 14:55
 * @description: redis分布式锁工具类
 */
public class SimpleRedisLock implements ILock {


    private String name;
    private StringRedisTemplate stringRedisTemplate;

    private static final String KEY_PREFIX = "lock:";
    //uuid用来区分不同的jvm 存入线程标识
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;//脚本
    //初始化静态脚本
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unLock.lua"));//脚本位置
        UNLOCK_SCRIPT.setResultType(Long.class);//返回类型
    }

    //构造函数传入
    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取线程标识 edc56a3844694bb1a10648357bb510c3-40  uuid-线程id
        String threadId = ID_PREFIX+ Thread.currentThread().getId();

        //获取锁 lock:order:1010
        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name,
                threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    //调用lua脚本实现释放锁
    @Override
    public void unlock() {
        // 调用lua脚本
        stringRedisTemplate.execute(//这是redis在java中调用lua的Api
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId());
    }

/*    @Override
    public void unlock() {
        //获取线程标识
        String threadId = ID_PREFIX+ Thread.currentThread().getId();

        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        if (threadId.equals(id)) {
            return;
        }
        //释放锁
        stringRedisTemplate.delete(KEY_PREFIX+ name);
    }*/

}
